Over the past year, Elon Musk, billionaire founder of PayPal, Tesla, and SpaceX, has been floating the notion of a "Hyperloop" as a future replacement for bullet trains; one that would get commuters from San Francisco to Los Angeles in as little as 30 minutes. There has been much speculation over how the Hyperloop works, as Musk has revealed very few details. So what has Musk actually said and what might this translate to in the real world?